| |
| Coastal
hill as a keystone community in the marine environment |
|
Nutrient
Producer for marine life
Rising steeply from the sandy beach to a height
of 21m, the coastal hill at Chek Jawa
may seemed remotely connected to the shallow sea beneath, where lush
meadows of seaweed and sea grasses thrived in the shallow, well-lit
and nutrient-rich waters. However, the link is very much alive though
not easily perceivable unless one witnesses how rainwater runs down
the hill during a monsoon downpour (see drawing).
Dissolved nutrients, along with guano, leaf detritus and rock
minerals, trickle down with the rainwater to the beach below,
where it is released slowly through the sand to the sea, and readily
absorbed by the marine flora or consumed by detritus feeding fauna.
Leached nutrients (Trono, 1997) and leaf detritus (Odum and Heald,
1975) are two of the most important elements in the food web that
associating landforms (including mangrove) contribute to the vitality
of the inter-tidal zone. |
The
abundance of marine flora and fauna in Chek Jawa bears testimony to
the importance of the coastal hill as a keystone community in the
marine environment (see map).
Physical buffer and natural breakwaters
Physically, the steep coastal hill is imposing. It is a natural fortress
make up of large igneous boulders that goes right down to the beach,
and act effectively as a buffer against casual intrusion to the sandy
beaches from inland. |
 |
| The obscurity
as well as the relatively undisturbed state of Chek Jawa owes much
to this rugged feature that are almost impregnable when aided by the
long hours of high tides. The coastline integrity of Chek Jawa owes
much to the series of protective finger-like boulders jutting out
to sea at the base of the hill. Like natural breakwaters, they offer
protection against accretion of the sandy beach. Without doubt, the
coastal morphology of Chek Jawa, predominantly truncated by these
mighty boulders, had evolved with the tidal flow to create the unique
marine features (including the lagoon) that we find today. |
Unique
flora and beach-dependent terrestrial fauna
Apart from being an ecological and protective partner to the marine
environment, the rocky coastal hill forest is a special habitat by
itself. It harbors a very unique primary flora that is distinctly
different from the terrestrial vegetation found further inland. These
are tenacious survivors in the plant kingdom, as equally adaptable
as plants found in the deserts. |
 |
| Coastal trees
such as the Seashore Nutmeg, Sea
Mangosteen and the Sea Olive are constantly
exposed to strong dry winds, salt sprays, high solar radiation and
temperature, and scrounging a living from nutrients obtain from its
own leaf detritus and animal guano. These are amongst the last remaining
stand of littoral plants that have survived the centuries undisturbed,
on extremely shallow soil found atop rock ledges and crevices, and
sandy substrates. One such rare tree, Mischocarpus
sundaicus, once common in Geylang, Changi and Ubin, cannot
be found elsewhere in mainland Singapore now. |
| A
flock of over 50 native Red Junglefowls
inhabits and breeds in this quiet coastal forest. At low tide, they
flock to the beach to eat worms, mollusks and other organisms. They
are dependent on the beach for food. The coastal forest, in turn,
depends on them and other rooting birds for their nutrient-rich guano. |
 |
| References:
Gavino C. Trono, Jr., 1997. Field Guide & Atlas of the Seaweed Resources
of the Philippines. A joint project undertaken by the Marine Environment
and Resources Foundation, Inc. (MERF) and the Department of Agriculture
under the Fisheries Sector Program – National Fisheries Outreach Plan
(FSP-NFOP) with the Bureau of Agricultural Research. Odum, W.E. and
E.J. Heald, 1975. The detritus-based mangrove community. In L.E. Cronin
(ed.), Estuarine Research, Academic Press, New York, Vol. 1, pp. 265-86.
|
Additional Reading: Find out how Clown
Anemonefishes need Rainforest
|